Wahoo Bike Case

Hi,
Im looking at the Wahoo Bike Case for iPhone for XC riding.

Im a stats junkie, so like the fact that my iphone app will take the speed and distance from the sensor from my wheel instead of the iphone GPS chipset which is always off by about 10%.
If your trail is in a lot of straight line it can do ok, but if your ride single tracks with a lot of switchback, your total distance will be wayyyyyyyyy off.

I use a bluetooth GPS with my iPhone (jailbreak) and I still get offset data if I compare it from my cateye.

So my question is, for those of you that tried that case, is it strong enough, tight enough, waterproof enough to stand strong abuse in the likes of heavy rain, lots of mud, dust, crash etc... ?

I carry my phone in my backpack but I would love to have it mount on my bar.